1. Field of the Invention
The present invention relates to a drive system of powered doors or gates for vehicles, more particularly to a drive system of a vertically openable rear gate pivotally attached to a vehicle body, which includes: a rack and pinion mechanism, a motor for driving the pinion, and a link member connected to the rack and the rear gate, etc.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 2001-253241 discloses a rear gate drive system which includes: a channel track provided along a vehicle rear pillar, a rack and pinion mechanism in which the rack is provided inside the track as slidable in the longitudinal direction thereof, and a link member connected to the rack and the rear gate. The rack is formed to have, on its upper end, a joint portion to which the link member is connected by a ball joint. The rear gate is opened/closed, as the rack is driven to move in the track by rotation of the pinion.
However, in the above drive system, the channel track is provided with a longitudinally extending slot, which the joint portion of the rack is protruded through and is guided by, as the rack moves in the track. Load on the joint portion, when the rear gate is opened/closed, is therefore transferred to the periphery of the slot, whereby, after repeated uses, the channel track is deformed into having an expanded slot which results in excess play impeding the smooth motion of the rear gate in a opening/closing operation.